During an exercise in March, Russian troops rehearsed how to invade four
regional neighbours

Russian forces rehearsed the invasion of Norway, Finland, Sweden and Denmark during a military exercise involving 33,000 troops, according to a new study of Baltic security.

The manoeuvres, which took place in March, assumed that a Western-backed uprising against President Vladimir Putin was taking place in Moscow. Under the scenario posited by the exercise, Russia responded by launching a simulated assault on four regional neighbours.

Some troops practised attacking Norway with the aim of seizing an area in the north of the country. Other Russian forces rehearsed the capture of the Aland islands from Finland. More units drilled how to seize Gotland island from Sweden and Bornholm island from Denmark.

“If carried out successfully, control of those territories would make it all but impossible for Nato allies to reinforce the Baltic states,” wrote Edward Lucas, the senior vice-president of the Centre for European Policy Analysis and the author of the report.

Of the countries targeted by this Russian exercise, Denmark and Norway are members of Nato, while Finland and Sweden are officially neutral. Mr Lucas argues that all four should enhance their military cooperation with other vulnerable states, particularly Estonia, Latvia, Lithuania and Poland.

The Kremlin’s military manoeuvres betray a preoccupation with achieving dominance of the Baltic – and a willingness to use nuclear weapons.

In June last year, Russian jets simulated a nuclear attack on Bornholm, timed to coincide with an annual festival on the Danish island involving the country’s entire political leadership and 90,000 guests. “Had the attack actually taken place, Denmark would have been decapitated,” writes Mr Lucas.

In March last year, a Boeing 737 from Scandinavian Airlines narrowly avoided a mid-air collision with a Russian IL-20 reconnaissance aircraft during a flight from Copenhagen to Rome.

Russian President Vladimir Putin

However, Russia would probably be unable to mount a real attack on any Baltic neighbour for as long as its forces are fighting in eastern Ukraine.

American officials believe that Russian regular troops are “integrated” with separatist rebels in Ukraine, providing them with weapons, training, logistics and command and control.

Russia and Ukraine have signed the Minsk agreements, providing for a ceasefire. But the bloodshed in the regions of Donetsk and Luhansk has escalated in recent weeks, with pro-Russian forces pressing closer towards the port city of Mariupol.

Daniel Baer, the US ambassador to the Organisation for Security and Cooperation in Europe, said that ceasefire observers were reporting more fighting, raising fears of a further escalation. Last weekend alone, the monitors noted 700 explosions by artillery shells or other projectiles in eastern Ukraine.

“You can’t sustain that without a state-sponsored procurement system, without a logistics system and without resupply,” said Mr Baer. “What is happening could not be happening without Russian participation.”